Schema Design Patterns

Common Schema Design Patterns

MongoDB schema design is application-driven. Several recurring patterns solve common problems elegantly.

• Bucket pattern — group time-series data into buckets (e.g. one document per hour of sensor readings) to avoid document-per-reading explosion
• Subset pattern — embed only the most recently accessed subset of a large array (e.g. last 10 comments) and store the rest in a separate collection
• Computed pattern — cache expensive aggregation results in the document and update them on write
• Outlier pattern — handle the rare document that breaks your size assumptions with an overflow flag and a linked collection
• Extended reference pattern — embed a small copy of the most-read fields from a referenced document to avoid frequent $lookup calls